btm24 Posted March 28, 2011 Share Posted March 28, 2011 I have never seen this before. When I went to check my air filter it had black oil on about 2/5th of it. Any ideas? I was thinking a vacuum leak but I checked and I don't have any so now I'm just lost. Is this something to really worry about? It seems like it would be. Brandon Link to comment Share on other sites More sharing options...
JENSSEN Posted March 28, 2011 Share Posted March 28, 2011 Weak engine, that's PCV blow by Link to comment Share on other sites More sharing options...
Eagle Posted March 28, 2011 Share Posted March 28, 2011 viewtopic.php?f=2&t=29388 This has been discussed many times here before. Link to comment Share on other sites More sharing options...
1987Comanche Posted March 28, 2011 Share Posted March 28, 2011 I worried about mine initially too ('90 4.0). I upgraded to a newer style valve cover with better baffles, made sure all the ccv lines were clean and it made a marginal difference. Ultimately I bought a cheap Fram Air Hog (their version of the K&N) and check it every 8K or so. The thing is completely oil soaked but since it's gauze it won't fall apart on me...it probably weighs 3 lbs by now. The oil coming out of the airbox on the Driver's side nicely balances the oil leaking from the head on the pass side. Link to comment Share on other sites More sharing options...
64 Cheyenne Posted March 28, 2011 Share Posted March 28, 2011 Every time I read about this and or a leaking rear seal I kick myself in the @$$ for not taking pics. Many say to upgrade to the newer baffle style valve cover, a person can, but there is an easier way. First get a breather for an HO engine(has a larger hose size), remove valve cover, remove towers and clean (you'll see what I mean by towers with the VC off). Drill a 3/8" hole midway up on both towers. Here is the tricky part, Just kidding do as I describe and you won't have any problems.Drill 3/16" hole in the HO breather orifice, larger is not better here. silicone (don't get ugly with the silicone, it is to seal, not hold in place) the HO breather into the VC without a grommet. then put 1 pop rivet in it on each side to keep it in place. Next, remove and replace the hose nipple on the intake (with the next larger size)Not sure but I think it is 3/8 pipe to 1/4 " hose. Reinstall valve cover. You will need 1/4" hose from the nipple then a piece of 1/2" hose? to join the 1/4'' to the HO breather. Mine and a few of my friends are this way now and all airboxes are bone dry. Point to mention, if a rear seal is leaking, and the airbox is full of oil, fix the VC first. Might even stop the seal leak, as the crankcase won't be under pressure anymore. Link to comment Share on other sites More sharing options...
4X4COMANCHE Posted March 29, 2011 Share Posted March 29, 2011 whats the worst that could happen if you just disconnected the hose? Link to comment Share on other sites More sharing options...
Eagle Posted March 29, 2011 Share Posted March 29, 2011 whats the worst that could happen if you just disconnected the hose? (a) You get oil all over the engine compartment (B) you get abrasive dust and dirt in your crankcase. Link to comment Share on other sites More sharing options...
64 Cheyenne Posted March 29, 2011 Share Posted March 29, 2011 I've heard of running the hose into a catch bottle, empty as needed. To me, actions like this are the beginning demise of that particular MJ. If a person doesn't fix it right, what is going to get skimped on next? I treat my MJs with a lot of love and care, I doubt I'll get the opportunity to buy many more of them. Think about when somebody who only for the sake of making a buck, says "those are getting rare, hard to find, Gotta have this much more$ because of that". MJs are special, I'm proud to own 2 that I'll never sell. Link to comment Share on other sites More sharing options...
Karlo Posted March 30, 2011 Share Posted March 30, 2011 Hi folks I'm new here and amazed at some of the utter pricelessness of the advice offered. Damn if I don't have a leaking rear oil seal too and here I discover it could be a VALVE COVER problem? @64Cheyenne could you take a few pics of your engineering and post them for us? Link to comment Share on other sites More sharing options...
tazer15 Posted March 30, 2011 Share Posted March 30, 2011 Every time I read about this and or a leaking rear seal I kick myself in the @$$ for not taking pics. Many say to upgrade to the newer baffle style valve cover, a person can, but there is an easier way. First get a breather for an HO engine(has a larger hose size), remove valve cover, remove towers and clean (you'll see what I mean by towers with the VC off). Drill a 3/8" hole midway up on both towers. Here is the tricky part, Just kidding do as I describe and you won't have any problems.Drill 3/16" hole in the HO breather orifice, larger is not better here. silicone (don't get ugly with the silicone, it is to seal, not hold in place) the HO breather into the VC without a grommet. then put 1 pop rivet in it on each side to keep it in place. Next, remove and replace the hose nipple on the intake (with the next larger size)Not sure but I think it is 3/8 pipe to 1/4 " hose. Reinstall valve cover. You will need 1/4" hose from the nipple then a piece of 1/2" hose? to join the 1/4'' to the HO breather. Mine and a few of my friends are this way now and all airboxes are bone dry. Point to mention, if a rear seal is leaking, and the airbox is full of oil, fix the VC first. Might even stop the seal leak, as the crankcase won't be under pressure anymore. I need to do this, when we got hellbilly it was soaked with oil in the airfilter and everything was a mess. I fig it was a clogged line, pcv, baffel or something along those lines.So i cleaned everything including VC replaced gasket and couple other small things.I'm guessing this won't last?Since you didnt take pics of this mod can you take pics of finished product?Or can you really not see anything?I lost you a little bit but I'm sure i can figure it out once i get it all in my hands.Thanks :cheers: Link to comment Share on other sites More sharing options...
64 Cheyenne Posted March 31, 2011 Share Posted March 31, 2011 Alright guys you forced me to do it, just kiddin, I told Brandon that I'd take some other pics for him. This will be easy enough to do while I'm at it. You need to understand that the only pics I can't take are the inside of the VC. Easy enough though, when the VC is off you will see 2 tower shaped protrusions. You drill the 3/8" hole midway up each of these. What is happening here is the tower is too close to the head, when the crank case sees vacuum or pressure, oil is sucked up or pushed up these tubes. the holes allow them to vent above the oil on the top of the head. Stay tuned for the rest of the story tomorrow. Link to comment Share on other sites More sharing options...
btm24 Posted March 31, 2011 Author Share Posted March 31, 2011 Thanks :wrench: Link to comment Share on other sites More sharing options...
64 Cheyenne Posted April 1, 2011 Share Posted April 1, 2011 Apologize for no pics or anything today. Gonna have to wait till this weekend as I'm a little overextending myself. Tomorrow is my Bday and finals are coming up very fast. Link to comment Share on other sites More sharing options...
Pete M Posted April 1, 2011 Share Posted April 1, 2011 it was an emergency thing done early in my moab trip, but the catch can does in fact work. :D I suggest the valve cover fix first. :thumbsup: Link to comment Share on other sites More sharing options...
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